Warranty (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jul. 31, 2016	Jul. 31, 2015	Jul. 31, 2016	Jul. 31, 2015
Warranty claim activity
Beginning balance	$ 1,000	$ 950	$ 1,000	$ 950
Provision	47	112	176	193
Costs incurred	(47)	(62)	(176)	(143)
Ending balance	$ 1,000	$ 1,000	$ 1,000	$ 1,000
Minimum [Member]
Warranty [Line Items]
Product warranty period			5 years
Maximum [Member]
Warranty [Line Items]
Product warranty period			10 years